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Publication numberUS4692651 A
Publication typeGrant
Application numberUS 06/844,330
Publication date8 Sep 1987
Filing date26 Mar 1986
Priority date29 Mar 1985
Fee statusPaid
Publication number06844330, 844330, US 4692651 A, US 4692651A, US-A-4692651, US4692651 A, US4692651A
InventorsAkira Hiramatsu, Hitoshi Mukohjima, Naoya Kaneda, Takuo Okuno, Hiroyuki Seki, Takayuki Tsukimoto, Kazuhiro Izukawa, Ichiro Okumura
Original AssigneeCanon Kabushiki Kaisha
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Vibration wave motor
US 4692651 A
Abstract
A vibration wave motor has a movable member divided into a plurality of sections in a direction of movement. Opposite ends of press-contact areas of the divided sections of the movable member to a vibration member are supported by a support member. The press-contact areas have a smaller rigidity than that of the support member.
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Claims(6)
What is claimed is:
1. A vibration wave motor comprising:
(a) vibration means having electro-mechanical conversion elements for generating a travelling vibration wave when electrical signals having a phase difference therebetween are applied to said elements; and
(b) movable means adopted to be frictionally driven by the travelling vibration wave generated in said vibration means, a press-contact portion of said movable means which is in contact with said vibration means being divided into a plurality of sections along a direction of movement of said movable means and the rigidity of the surface of said divided press-contact portion, which is parallel with a forward moving direction of the travelling vibration wave, being lower than that of the surface of said divided press-contact portion, which is perpendicular to the forward moving direction of the travelling vibration wave.
2. A vibration wave motor according to claim 1, wherein said movable means has ring shape.
3. A vibration wave motor according to claim 1, wherein said press-contact portion is formed to be U-shaped.
4. A vibration wave motor comprising:
(a) vibration means having electro-mechanical conversion elements for generating a travelling vibration wave when electrical signals having a phase difference therebetween are applied to said elements; and
(b) movable means adopted to be frictionally driven by the travelling vibration wave generated in said vibration means, said movable means having a press-contact portion, which is in contact with said vibration means, being divided into a plurality of sections along a direction of movement of said movable means, wherein each of said plural sections has a torque transmission member which is in contact with said vibration member, and a supporting member for supporting said torque member, and the rigidity of said supporting member being lower than that of said torque transmission member.
5. A vibration wave motor according to claim 4, wherein said supporting member is adopted to support said torque transmitting member so that said torque transmitting member is maintained in parallel with said vibration means.
6. A vibration wave motor according to claim 5, further comprising a vibration absorbing member filling the U-shaped space of said press-contact portion.
Description
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vibration wave motor which excites a vibration member by using an electromechanical transducing element to drive a movable member coupled to the vibration member.

2. Description of the Prior Art

Many proposals have been made on the vibration wave motor. A principle of the vibration wave motor is shown in FIG. 1. Numeral 1 denotes an elastic member which is a vibration member and excited by a piezo-electric device or electrostrictive device (not shown) to generate a travelling wave on a surface of the elastic member 1 as shown. Considering a mass point a on the surface of the elastic member, it vibrates longitudinally and laterally and makes an eliptical motion as shown. Numeral 2 denotes a rotor which is press-contacted to the elastic member 1 at a pressure P and driven in a direction of an arrow A by a lateral motion component of the eliptical motion of the mass point.

An amplitude of the eliptics which is a locus of motion of the mass point is very small such as several microns to several tenths microns. Thus, it is necessary to precisely finish the contact areas of the elastic member 1 and the rotor 2.

The contact area is slightly deformed by the pressure applied to contact the rotor 2 to the elastic member 1. Thus, it is difficult to attain uniform contact over the entire contact area. As a result, motor efficiency is lowered and noise is generated.

In order to resolve the above problems, Japanese Unexamined Patent Publication No. 178987/1984 discloses an approach in which the rotor is divided into a plurality of sections which are independently contacted to the contact areas. The disclosed technique is incomplete because when the vibration generated in the vibration member includes a torsional component, the rotor is obliquely contacted to the elastic member by the torsional component. Therefore, uniform contact of the elastic member and the rotor over the entire contact area is not attained.

Japanese Unexamined Patent Publication No. 188381/1984 discloses a vibration wave motor which comprises a slider constructed by dividing a rotor and a rubber elastic member for supporting the slider. In the disclosed technique, since the slider is supported by the rubber elastic member, the slider may be inclined in any direction. Thus, when the slider is driven by the lateral motion component of the eliptical motion of the mass point of the elastic member, the motion component is absorbed by the rubber elastic member as the slider is inclined so that torque is not effectively transmitted.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a vibration wave motor which enables uniform press-contact of a plurality of contact areas of a rotor to an elastic member and constant press-contact between the elastic member and the rotor for any change of the contact force so that the efficiency of the motor is improved and a noise is reduced.

It is another object of the present invention to provide a vibration wave motor which resolves the problems encountered in the prior art motor and is easy to construct.

It is another object of the present invention to provide a vibration wave motor which can reduce vibration at an undesired frequency.

It is another object of the present invention to provide a vibration wave motor having a small warp slider.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a principle of a vibration wave motor,

FIG. 2 is a developed perspective view of one embodiment of a vibration wave motor of the present invention,

FIG. 3 shows a sectional view of the vibration wave motor shown in FIG. 2, and

FIGS. 4 to 6 show enlarged views of sections of rotors in the embodiments of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2 shows a developed perspective view of a vibration wave motor of the present invention, and FIG. 3 is a sectional view of the vibration wave motor shown in FIG. 2. Numeral 1 denotes an elastic member to which a piezo-electric or electrostrictive device 3 is bonded. When two periodic voltages having a phase difference (e.g. 90) therebetween are applied to the piezo-electric or electrostrictive device 3, the elastic member 1 is excited to generate a travelling wave as shown in FIG. 1. Numeral 4 denotes a slider which is press-contacted to the elastic member 1. It is divided into a plurality of (eight in FIG. 2) sections. The slider 4 is bonded to a hold plate 5 to form a rotor 2. Numeral 5a denotes a groove in the hold plate and numeral 5b denotes an output area of the motor. Numeral 6 denotes a vibration absorbing member made of rubber or felt to hold the piezo-electric or electrostrictive device, numeral 7 denotes a pressurizing mechanism for generating contact pressure for the elastic member 1 and the rotor 2, and numerals 8 and 10 denote holding cylinders for holding the elastic member 1 and the rotor 2 therebetween. The contact pressure between the elastic member 1 and the rotor 2 is adjusted by a thread 8a on the upper holding cylinder 8 and a thread 10a of the lower holding cylinder 10. The rotor 2 is rotatably held by the groove 5a of the hold plate 5 and a bearing 9.

FIG. 4 shows an enlarged sectional view of the rotor 2. Numeral 4a denotes a contact area which is press-contacted to the elastic member 1, and numeral 4b denotes a hold area to hold the contact area 4a. The areas 4a and 4b form a contact surface to the elastic member 1. Numeral 4c denotes support areas which support opposite ends of the hold area 4b.

The hold area 4b has a sufficiently lower rigidity than those of the support area 4c and the contact area 4a. When the rotor 2 is pressed at the pressure P by the pressurizing mechanism 7, it is press-contacted to the elastic member 1 at the contact area 4a.

The contact area 4a is pressed by a counterpressure p by the elastic member 1, but since the rigidity of the hold area 4b is sufficiently lower than that of the support area 4c and the contact area 4a, the hold area 4b is deformed as shown by a broken line by the counterpressure p.

Since the slider 4 is constructed by the plurality of sets of contact areas 4a, hold areas 4b and support areas 4c. The contacts areas 4a of the slider 4 are uniformly contacted to the contact surface 1a of the elastic member 1, and even if the vibration generated in the elastic member 1 includes a torsional component, the hold areas 4b deform accordingly so that the hold areas 4b are always uniformly contacted.

FIG. 5 and 6 show other embodiments of the present invention. In FIG. 5, the contact area 4a is supported by a pair of leaf springs 11a and 11b, which are deformed by a counterpressure p as shown by broken lines.

In FIG. 6, the slider 4 is constructed by a thin plate. Since it may be manufactured by pressing, cost can be reduced compared to the embodiments shown in FIGS. 4 and 5 and precision is improved. The slider 4 is mounted and fixed to the support plate 5. The present embodiment presents the some advantage as that of the embodiment of FIG. 4.

By filling spaces of the rotor in the embodiments of FIGS. 4-6 with vibration absorbing material such as silicone rubber, the rubber acts as a damper to reduce vibration at an undesired frequency. The rotor and the slider may be bonded by silicon filler.

By filling the spaces of the rotor as well as the spaces between the divided sliders 4 shown in FIGS. 4 to 6, with vibration absorbing material, warpage of the divided sliders can be reduced.

The hold area 4b in embodiment of FIG. 4, the leaf springs 11a and 11b shown in FIG. 5 and the thin plate slider 4 shown in FIG. 6 may be made of plastic to reduce the rigidity or they may be made of spring materials or other resilient materials.

In the above embodiments, rotary motors have been shown and described. The present invention can also be applied to a linear vibration wave motor in which the movable member is linearly moved.

As described hereinabove, in accordance with the present invention, the slider of the movable member is divided into the plurality of sections and the contact areas of the slider are resiliently held such that they have a low rigidity normal to the contact area and a high rigidity parallel with to the contact area. Thus, the slider sections of the movable member are uniformly contacted to the elastic member and the partial contact in which the movable member is only partially contacted to the elastic member can be prevented.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US4495432 *5 Dec 198322 Jan 1985Canon Kabushiki KaishaPiezoelectric vibration wave motor with sloped drive surface
US4562374 *16 May 198431 Dec 1985Toshiiku SashidaMotor device utilizing ultrasonic oscillation
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4797689 *28 Dec 198710 Jan 1989Eastman Kodak CompanyUltrasonic vibration driving type thermal printer
US4829209 *17 Feb 19879 May 1989Matsushita Electric Industrial Co., Ltd.Ultrasonic motor with stator projections and at least two concentric rings of electrodes
US4871937 *15 Mar 19883 Oct 1989Olympus Optical Co., Ltd.Vibration wave motor
US4882500 *19 Sep 198821 Nov 1989Nippon Seimitsu Kogyo Kabushiki KaishaMethod for converting standing wave vibrations into motion and standing wave motor therefor
US4918351 *7 Apr 198917 Apr 1990Olympus Optical Co.Vibration wave motor
US5017823 *18 Sep 198921 May 1991Canon Kabushiki KaishaVibration wave driven actuator
US5028833 *15 May 19902 Jul 1991Olympus Optical Co., Ltd.Ultrasonic motor
US5062622 *18 Jan 19905 Nov 1991Canon Kabushiki KaishaVibratory sheet feeder which uses phase adjustment to control the sheet feeding speed
US5091670 *13 Jun 199025 Feb 1992Seiko Instruments Inc.Ultrasonic motor
US5099166 *14 Sep 198924 Mar 1992Canon Kabushiki KaishaVibration wave driven motor
US5140214 *6 Sep 199018 Aug 1992Canon Kabushiki KaishaVibration wave driven apparatus
US5159253 *25 Jun 199127 Oct 1992Canon Kabushiki KaishaControl device for a vibration wave motor
US5176376 *29 Aug 19915 Jan 1993Canon Kabushiki KaishaVibration sheet feeder
US5187406 *27 Aug 199116 Feb 1993Canon Kabushiki KaishaVibration driven motor
US5189331 *12 Dec 199123 Feb 1993Canon Kabushiki KaishaVibration wave driven motor
US5192890 *3 Jun 19929 Mar 1993Canon Kabushiki KaishaVibration driven actuator
US5298829 *1 Feb 199129 Mar 1994Canon Kabushiki KaishaVibration wave driven motor
US5300850 *30 Jan 19925 Apr 1994Canon Kabushiki KaishaVibration wave motor
US5313132 *18 May 199217 May 1994Canon Kabushiki KaishaElastic supporting member for a vibration driven motor
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US5408156 *23 Apr 199018 Apr 1995Matsushita Electric Industrial Co., Ltd.Ultrasonic motor
US5440192 *25 Apr 19948 Aug 1995Seiko Instruments Inc.Ultrasonic motor
US5484216 *1 Dec 199316 Jan 1996Canon Kabushiki KaishaSupporting device for a vibration driven actuator
US5508580 *26 Aug 199416 Apr 1996Canon Kabushiki KaishaVibration wave driven motor
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US5821669 *10 Jun 199713 Oct 1998Samsung Electronics Co., Ltd.Vibration wave motor having piezoelectric pressure member
US5945771 *10 Sep 199731 Aug 1999Canon Kabushiki KaishaVibration wave driven motor and a printing apparatus
US5949178 *22 Apr 19967 Sep 1999Canon Kabushiki KaishaVibration wave driving apparatus and a vibration member, and manufacturing method of the apparatus and the member
US61982012 Jun 19996 Mar 2001Canon Kabushiki KaishaVibration wave apparatus
US638066011 May 200030 Apr 2002Canon Kabushiki KaishaVibration type actuator and vibration type driving apparatus
US662804615 Apr 200230 Sep 2003Canon Kabushiki KaishaVibration type actuator
US678128317 Jan 200224 Aug 2004Canon Kabushiki KaishaVibration element and vibration wave driving apparatus
US688828820 Dec 20023 May 2005Canon Kabushiki KaishaVibration member and vibration wave driving apparatus using the vibration member
US693043615 Jan 200216 Aug 2005Canon Kabushiki KaishaVibration element and vibration wave driving apparatus
US698962430 Sep 200424 Jan 2006Canon Kabushiki KaishaVibration element and vibration wave driving apparatus
US721506320 May 20058 May 2007Canon Kabushiki KaishaVibration element and vibration wave driving apparatus
US88165681 Jun 201126 Aug 2014Canon Kabushiki KaishaVibration-type driving apparatus
USRE36337 *4 Jun 199312 Oct 1999Olympus Optical Co., Ltd.Ultrasonic motor
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Classifications
U.S. Classification310/323.09, 310/328
International ClassificationH01L41/09, H02N2/16, H02N2/00
Cooperative ClassificationH02N2/163
European ClassificationH02N2/16B
Legal Events
DateCodeEventDescription
29 Jan 1999FPAYFee payment
Year of fee payment: 12
27 Jan 1995FPAYFee payment
Year of fee payment: 8
31 Oct 1990FPAYFee payment
Year of fee payment: 4
9 Feb 1988CCCertificate of correction
26 Mar 1986ASAssignment
Owner name: CANON KABUSHIKI KAISHA, 30-2, 3-CHOME, SHIMOMARUKO
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:HIRAMATSU, AKIRA;MUKOHJIMA, HITOSHI;KANEDA, NAOYA;AND OTHERS;REEL/FRAME:004533/0157
Effective date: 19860324